Effect of injection strategies on particulate matter emissions from HPDI natural-gas engine
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Faghani, Ehsan
issued: 2015-12-01T03:18:19
issued: 2015
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Internal combustion engines produce emissions of NOx and particulate matter (PM). Westport Innovations Inc. has developed the pilot-ignited high-pressure direct-injection (HPDI) natural gas (NG) engine system. To ignite the natural gas, HPDI uses a small diesel pilot injection (~5% of total fuel energy), which is normally injected before the NG. Although HPDI engines produce less PM than diesel engines, further reductions of engine-out PM emissions are desired in order to meet future regulations. The goal of this project is to reduce PM from HPDI engines and study the drawbacks of the injection strategies in terms of engine performance or other emissions. This thesis proposes mechanisms for two injection strategies useful in PM reduction: Late Post Injection (LPI) and Slightly Premixed Combustion (SPC). Tests on LPI and SPC were performed in the UBC Single Cylinder Research Engine (SCRE). In LPI, a second natural gas injection (10-25% of total fuel mass) is injected into the cylinder later in the cycle. In SPC, more premixing of NG is achieved by injecting NG before the diesel injection and engine operating parameters are adjusted to minimize the effect on other emissions. Both of the injection strategies show significant PM reduction (over 75% on the SCRE) with small effects on other emissions and engine performance. Westport’s computational fluid dynamics package, “GOLD”, was used to help to understand the mechanisms of the new injection strategies. The PM reductions from LPI and SPC were captured by GOLD. A phenomenological model (Transient Slice Model, TSM) has been developed in this study to provide better insight into the PM reduction process, using the Hiroyasu model with a transport equation for soot. TSM results show good agreement in the prediction of pressure trace and heat release rates in most cases. Engine-out PM trends with changing engine parameters are well-captured in the TSM for exhaust gas recirculation (EGR), equivalence ratio (EQR), load and na…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/55606
note: EFFECT OF INJECTION STRATEGIES ON PARTICULATE MATTER EMISSIONS FROM HPDI NATURAL-GAS ENGINES by EHSAN FAGHANI B.Sc., The University of Tehran, 2005 M.Sc., Sharif University of Technology, 2008 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) November 2015 © Ehsan Faghani, 2015 ii ABSTRACT Internal combustion engines produce emissions of NOx and particulate matter (PM). Westport Innovations Inc. has developed the pilot-ignited high-pressure direct-injection (HPDI) natural gas (NG) engine system. To ignite the natural gas, HPDI uses a small diesel pilot injection (~5% of total fuel energy), which is normally injected before the NG. Although HPDI engines produce less PM than diesel engines, further reductions of engine-out PM emissions are desired in order to meet future regulations. The goal of this project is to reduce PM from HPDI engines and study the drawbacks of the injection strategies in terms of engine performance or other emissions. This thesis proposes mechanisms for two injection strategies useful in PM reduction: Late Post Injection (LPI) and Slightly Premixed Combustion (SPC). Tests on LPI and SPC were performed in the UBC Single Cylinder Research Engine (SCRE). In LPI, a second natural gas injection (10-25% of total fuel mass) is injected into the cylinder later in the cycle. In SPC, more premixing of NG is achieved by injecting NG before the diesel injection and engine operating parameters are adjusted to minimize the effect on other emissions. Both of the injection strategies show significant PM reduction (over 75% on the SCRE) with small effects on other emissions and engine performance. Westport’s computational fluid dynamics package, “GOLD”, was used to help to understand the mechanisms of the new injection strategies. The PM reductions from LPI and SPC were captured by GOLD. …
has type: Thesis/Dissertation
date issued: 2016-02
is shown at: 10.14288/1.0220518
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/55606